Undisturbed sampling and laboratory shearing tests on a sand with various fines contents

Abstract

The effects of plastic or non-plastic fines on the static and cyclic strength of sand have been a subject of laboratory studies for many decades. These studies have not lead to a concensus as to how fines can affect the behavior of sand. Earlier studies have mostly been limited to tests on reconstituted specimens. Some of the controversies stem from the concerns that reconstituted specimens may not be able to duplicate the soil fabric in the field. The authors used Laval sampler to retrieve high quality samples with a wide range of fines contents in Central Western Taiwan. A test site was developed in Yuan Lin Township where standard penetration test (SPT), seismic piezocone (SCPTU) and field shear wave velocity (V-s) measurements were performed in addition to Laval sampling. A series of monotonic and cyclic triaxial tests with V-s measurements were conducted on natural and reconstituted Yuan Lin Soil (YLS) specimens with fines contents ranging from 18 to 89%. While the study confirmed some of the earlier findings which indicated that fines tend to weaken the soil specimens, the results also showed that the effects of fines may be exaggerated according to tests on reconstituted specimens.